In general, snowmaking is accomplished by atomizing water into tiny droplets which are projected through the colder atmospheric air in contact of which the droplets freeze into crystalline particles of ice before falling in the form of man-made snow. A snowmaking device utilizing compressed air to atomize, and to project the atomized water droplets is more specifically disclosed in our earlier U.S. Pat. Nos. 4,759,503; 4,793,554 and 4,915,303. There is, however, a different type of snowmaking machine disclosed in U.S. Pat. Nos. 4,214,700; 4,493,457 and 4,711,395. This type of device utilizes a motor driven fan for moving large volumes of air at ambient temperature to form a semi-coherent stream of air. Virtually all of these types of snowmaking devices comprise at their fan outlet a multitude of high-pressure water atomizer nozzles which disintegrate the device supplied snowmaking water into tiny droplets. The droplets are projected through a predetermined trajectory along which they freeze in contact with the colder air into crystalline particles of ice before falling to the ground. There are, however, climatic conditions such as marginal temperature and/or high humidity which do not allow all the projected water droplets to completely freeze; and thus, a substantial portion of the projected droplets fall unfrozen an the previously fallen snow, thereby causing undesirable snow conditions. The water atomizer nozzles in virtually all fan type snowmaking machines depend on a constant water pressure to produce and maintain a specific droplet size. A single water flow control valve located substantially upstream of the aggregate of atomizer nozzles tends to change the water pressure at each nozzle, and therefore change the water droplet size to an undesirable degree. For this reason, each of the water atomizer nozzles is provided with its own manually operated water valves, the operation of which does not compromise the water droplet size. When the conditions for making snow are marginal, it is necessary that some of the water flow control valves must be manually either opened or closed to compensate for frequently changing atmospheric conditions. That is to say, as e.g., the atmospheric temperature decreases, some of the individual water flow control valves may progressively be opened to cause a greater water flow, thereby producing a greater amount of snow. Whereas, as the atmospheric temperature increases, some of the water flow control valves must progressively be closed so as to limit the total water flow, thereby producing a lesser amount of snow. The individual water flow control valves in the prior art are operated according to fluctuating atmospheric conditions being monitored by means of conventional temperature and humidity gauges, none of which are an integral part of the snowmaking system itself. The condition of the man-made snow in the prior art is therefore solely dependent on how the operator interprets the atmospheric conditions before the snow is made, as well as on an ability to analyze the freshly made snow and consequently on a decision as to whether or not a hydrant readjustment must be made. The main disadvantage of the fan type snowmaking devices of the prior art is therefore their undesirably high labor intensity, as well as being cumbersome and difficult to operate.
In contrast thereto, the method of the present invention utilizes only one continuously operating, noncontact, infrared radiant energy measuring transducer (hereinafter referred to as the IR transducer) which generates an electric output directly proportional to the percentage of water to solidly frozen particles in the snow. The IR transducer produced electric output is utilized in combination with a servomechanism, or servomotor operated water valve to regulate a snowmaking device supplied water flow, so as to automatically produce and to maintain a desired snow condition without human attention.
Accordingly, the present invention in the preferred as well as in the alternate embodiment may be defined as an important improvement embodied in the form of automatic control adaptable to conventional, manually operated snowmaking devices of the prior art; wherein, as the average temperature of freshly made snow decreases, the embodiment of the present invention causes the water flow through the snowmaking device to increase; and conversely, as the average snow temperature increases, the embodiment of the present invention causes the water flow to decrease. Thereby maintaining the fundamentally inverting relationship between the snow temperature and water flow.